It is desired that reference current of analog circuitry is generated without causing variation in its current value. However, in a conventional reference current generating circuitry, the current value of the reference current depends on the element values (e.g., resistance value, capacitance value, etc.) of passive elements. On-chip analog circuitry has a problem that the current value of the reference current varies depending on manufacturing variability of the passive elements, which are difficult to manufacture with high accuracy. Further, using off-chip passive elements, which can be manufactured with high accuracy, leads to a problem that the cost of the analog circuitry increases.